1. Field of the Invention
The invention relates to an optical scanner for scanning incident light two-dimensionally by oscillatory rotation of a reflective surface on which light is incident, and an image forming apparatus having such an optical scanner, and more particularly to improvements in construction of the optical scanner.
2. Description of the Related Art
There is already known an optical scanner for scanning light, which is of a type in which incident light is scanned two-dimensionally by oscillatory rotation of a reflective surface on which light is incident (See, for example, FIGS. 7 and 8 of Japanese Patent Application Publication No. 2000-111829).
Such an optical scanner is for use in the fields of, for example, image formation and image reading. In the field of image formation, such an optical scanner is applied to retinal scanning display devices which scan a beam of light on the retina of a viewer for direct presentation of an image onto the retina; projectors; laser printers; devices for use in laser lithography; or other applications. In the field of image reading, such an optical scanner is applied to facsimile machines; copiers; image scanners; bar-code readers; or other applications.
For such an optical scanner, in some cases, there are strong needs of a reduction in size and weight, which are satisfied by an exemplary conventional optical scanner disclosed in the aforementioned Japanese Patent Application Publication No. 2000-111829.
More specifically, in the above exemplary conventional optical scanner, horizontal and vertical scanning devices are disposed in series in a direction in which light travels, in the order set forth above. These horizontal and vertical scanning devices are configured to cause respective mirror portions having respective reflective surfaces formed thereon, to angularly oscillate about corresponding respective oscillation axes, to thereby scan light which has obliquely entered the respective reflective surfaces. The mirror portions of the horizontal and vertical scanning devices are formed on the same substrate, resulting in coplanar disposition of the reflective surfaces of these mirror portions.